Waterproof tape for automobile battery and manufacturing method thereof

ABSTRACT

The present invention provides a waterproof tape for an automobile battery which comprises a filler layer having formed on one side of a base film to exhibit excellent viscosity while being thin and has excellent shock resistance and an excellent waterproof property, and a manufacturing method.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a waterproof tape for an automobilebattery and a manufacturing method, and more particularly to awaterproof tape for an automobile battery and a manufacturing method,which can effectively prevent penetration of water from a tight gap oncomponents of an automobile battery assembly while being thin, andprevent damage caused by external impacts with excellent shockresistance.

Description of the Related Art

Generally, all automobiles contain various required equipment necessaryfor the operation thereof, including an ignition system for driving anengine, most of which is operated by electric power. Hence, theautomobile includes a generator for supplying necessary power to devicesusing the electric power as power sources, wherein since the generatoris driven by the engine, it always includes a battery for supplyingoperation power to the starting ignition system thereof. Further, thebattery is connected to various electric units as well as the ignitionsystem so as to operate each of the electric units as needed when theengine is not driven, and reversely, when the engine is being driven,the battery is charged by the generator.

Such a battery is generally installed in an engine room where variousunits are concentrated. However, since the automobile engine room isformed such that the front and the bottom thereof may communicate withthe outside for radiating and cooling, particular attention towaterproofing of the battery is required. Thus, the battery is mountedto be located on a water level from the ground to the extent that theoperation thereof is not disrupted, called, on the top of a wading line,even if there are puddles in a running rail of the automobiles like therainy season, and the battery is waterproof in the structure thatrainwater and the like penetrated from the top can be blocked.

However, for example, when a flooding part of the automobile is beyondthe wading line by heavy rain and the like, the battery is wet toadversely affect the automobile operation as well as shortening abattery lifetime. Specifically, since a military truck is frequentlydriven underwater in the wading of a river, and the like, the problemfrom flooding of the battery becomes very serious. Thus, in the militarytruck, the battery might be installed in the inside of the truck. Inthis case, the battery can be waterproofed, but passengers have been toodissatisfied with harmful gas generated for the chemical reaction of thebattery.

To solve such a problem, a scheme of mounting the battery outside theautomobile on the top of the wading line is being pursued, but it isvirtually impossible to install the battery outside the automobile byallowing the battery to come close to the engine room on the top of thewading line in view of the structural characteristic of the automobile.

Hence, a waterproof tape having an adhesive layer formed on a basethereof is being used according to various purposes such as connection,fixation and the like, of the components in the battery. Further, it hasbeen known that in prior art waterproof tapes, for example, a foamingagent is used as the base to increase adhesion to an adhered object.

However, recently, as the automobile battery becomes smaller, lighterand thinner, and become more precise, it requires stricter watertightness. As a result, it is difficult to provide a waterproof propertymeeting such recent needs only by using the foaming agent as the base,and specifically, the tape finds difficulty in providing adhesion andwaterproof properties at a level capable of sufficiently covering even afew gaps present in a member and an interface of the adhesive layer.

Furthermore, the waterproof tape can have the functions such as shockresistance and shock absorption, in addition to basic roles such asadhesion, water proofing, and the like. That is, the waterproof tape canserve as preventing the adhered objects from being damaged by absorbinga shock force without damage of the tape from the shock force applied tothe adhered objects, simultaneously with preventing water from beingpenetrated between the adhered objects.

Conventional tapes have the foaming agents as the bases which maypartially serve as such shock resistance and shock absorption. However,when the tapes are narrow or thin, they have the problem ofinsufficiently implementing the shock resistance and shock absorptionfunctions.

PRIOR-ART DOCUMENT Patent Document

(Patent Document 1) Japanese Laid-Open Patent Publication No.2001-152111

(Patent Document 2) Korean Laid-Open Patent Publication No. 2002-0014120

SUMMARY OF THE INVENTION Technical Problem

The present invention was made to solve the aforementioned problemoccurring in the prior art, and it is an object of the present inventionto provide a waterproof tape for an automobile battery which exhibitsexcellent viscosity, adhesion and shock resistance to an adhered objectwhile being thin, in order to maximize watertightness of the automobilebattery and has a water-proof property at a level capable of effectivelycovering even a few gaps present in a member and an interface of anadhesive layer, and a manufacturing method.

Technical Solution

The present invention provides a waterproof tape for an automobilebattery and a manufacturing method. A double-sided tape comprises a basefilm having a filter layer formed on the side thereof and an adhesivelayer, wherein the filler layer comprises a shock resistant fillercontaining an acrylic binder and a plurality of hollow fine particles,and the hollow fine particle comprises a first coating film whichconsists of a thermoplastic material containing 15-40 parts by weight ofa monomer, with respect to a total of 100 parts by weight, and has ahollow part.

In accordance with another preferable embodiment, the hollow fineparticles may further comprise a second coating film containing 50-80parts by weight of calcium carbonate, with respect to a total of 100parts by weight, and disposed arranged along the circumference of thefirst coating film.

In accordance with another preferable embodiment, the filler layer maycomprise 5-60 parts by weight of the shock resistant filler, withrespect to 100 parts by weight of the acrylic binder.

In accordance with another preferable embodiment, the monomer of thefirst coating film may be a copolymer comprising at least one of 15-40parts by weight of acrylonitrile, with respect to 100 parts by weight ofthe hollow fine particles, phosphate methacrylate and alkali strippablepolyester acrylate.

In accordance with another preferable embodiment, the base film hasturned black, and the black coloring agent may comprise at least one ofcarbon black and iron sulfide.

In accordance with another preferable embodiment, the filler layer hasturned black, and the black coloring agent may comprise at least one ofcarbon black and iron sulfide.

An embodiment of the present invention provides a method formanufacturing a waterproof tape for an automobile battery by forming anadhesive layer on at least one side of a base film, wherein the basefilm forms a filler layer by coating a paste containing a shockresistant filler having an acrylic binder and a plurality of hollow fineparticles on one side thereof, and the hollow fine particles aremanufactured by the steps of: preparing a hydrogen dispersion byinputting 2-6 parts by weight of liquid hydrocarbon with respect to atotal of 100 parts by weight and a dispersing agent into water;preparing a particulate crystal by inputting 15-40 parts by weight of amonomer into the hydrogen dispersion, with respect to a total of 100parts by weight of the hollow fine particles, and forming a firstcoating film on the circumference of the hydrocarbon; forming anunexpanded microsphere by heating the particulate crystal and removingthe hydrocarbon; and preparing an expanded microsphere by heating theunexpanded microsphere to expand the first coating film.

In accordance with another preferable embodiment, the hollow fineparticles may be manufactured by further comprising the step of forminga second coating film with 50-80 parts by weight of calcium carbonate,with respect to a total of 100 parts by weight of the hollow fineparticles, on the circumference of the first coating film of theexpanded microsphere.

In accordance with another preferable embodiment, in the step ofpreparing the hydrogen dispersion, the liquid hydrocarbon may comprise1-10 parts by weight of 2-methylbutane and 1-10 parts by weight of2-methylpropane, with respect to a total of 100 parts by weight of thehollow fine particles.

In accordance with another preferable embodiment, in the step ofpreparing the hydrogen dispersion, the dispersing agent may be asurfactant.

In accordance with another preferable embodiment, in the step ofpreparing the particulate crystal, the monomer may be a copolymer of15-40 parts by weight of acrylonitrile with respect to a total of 100parts by weight of the hollow fine particles, and other acrylic groups.

In accordance with another preferable embodiment, in the step ofpreparing the expanded microsphere, the unexpanded microsphere may beheated at a temperature of 170-190° C.

In accordance with another preferable embodiment, the step of formingthe second coating film may comprise the steps of: inputting theexpanded microsphere and the calcium carbonate into a reactor, andinserting air thereto at a temperature of 130-150° C., thereby floatingthe expanded microsphere and the calcium carbonate inside the reactor;and forming a second coating film while embedding the calcium carbonatein an outer wall of the first coating film of the expanded microsphere.

In accordance with another preferable embodiment, the base film hasturned black, and the black coloring agent may comprise at least one ofcarbon black and iron sulfide.

In accordance with another preferable embodiment, the filler layer hasturned black, and the black coloring agent may include at least one ofcarbon black and iron sulfide.

Effects of the Invention

The waterproof tape for an automobile battery according to the exemplaryembodiment of the present invention exhibits excellent adhesion to anadhered object while being thin, thereby effectively preventingpenetration of water from a tight gap on a component of an automobilebattery assembly, and has excellent shock resistance to prevent damagecaused by external impacts, even if the tape is narrow or thin.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side sectional view of a waterproof tape according to anexemplary embodiment of the present invention.

FIG. 2 is a graph showing the result of comparing adhesion tests betweenembodiments of the present invention and comparative examples.

FIG. 3 is a graph showing the result of comparing shock resistance testsbetween embodiments of the present invention and comparative examples.

FIG. 4 is a flowchart of a method for manufacturing a waterproof tapeaccording to an exemplary embodiment of the present invention.

FIG. 5 is a flowchart of a method for manufacturing a shock resistantfiller of a filler layer in the waterproof tape according to anexemplary embodiment of the present invention.

FIG. 6 is a configuration view of schematically showing a reactor forforming a second coating film on an expanded microsphere according to anexemplary embodiment of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Hereinafter, exemplary embodiments in the present disclosure will bedescribed in detail with reference to the accompanying drawings. Thedisclosure may, however, be exemplified in many different forms andshould not be construed as being limited to the specific embodiments setforth herein.

Unless explicitly stated to the contrary, the word “comprise,”“comprises” or “comprising” used throughout the specification will notbe understood as the exclusion of the other elements but to imply theinclusion of the other elements.

FIG. 1 is a side sectional view of a waterproof tape according to anexemplary embodiment of the present invention.

With reference to FIG. 1, a waterproof tape 100 is basically configuredto arrange an adhesive layer on at least one of a base film 10 having afiller layer 20. In the exemplary embodiment, it is shown and describedthat first and second adhesive layers 30, 40 are respectively arrangedon both sides of the base film10, but the adhesive layer can be formedonly on an upper side of the filler layer 20 or on an upper part of thebase film 10, as needed.

Herein, the waterproof tape 10 may be formed, for example, at athickness of 10-300 μm so as to easily secure adhesion to an adheredobject. The thickness of the tape 100 is formed like this, and thus canbe easily applied in assembling an automobile battery assembly, and canimplement a favorable waterproof function as well as increasing theadhesion.

The base film 10 which is a layer to be a base of the tape 100, is usedfor fixation and the like of electronic and mechanical parts of theautomobile battery assembly, and may be preferably formed ofpolyethylene terephthalate (hereinafter referred to as “PET”), but thepresent invention is not limited thereto. For example, the base film 10may be manufactured by applying graphite with excellent heat resistanceand heat conductivity or a conductive material for the addition ofradiating and conductive functions.

Further, for example, a urethane base and the like may be applied to aprimer applied to the base film 10, but the present invention is notlimited thereto. The PET has an advantage of securing workability ofeasily removing the tape when the defects were generated due to wrongassembling at the adhesive layer, and reassembling as needed.

Further, the thickness of the base film 10 may be, for example, 20-40μm. For example, when a total thickness of the tape 100 is 250 μm orless, the thickness of the base film 10 may be about 23 μm, and when thetotal thickness of the tape 100 is greater than 250 μm, and, forexample, the total thickness is about 300 μm, the thickness of the basefilm 10 may be about 38 μm.

Herein, when the thickness of the base film 100 is less than 20 μm, theproblem of lowering heat resistance of the tape 10 and shortening amaterial may occur, and when the thickness of the base film 10 isgreater than 40 μm, because the filler layer 20, the first and secondadhesive layers 30, 40 and the like should be relatively thinly formed,the shock resistance and the adhesion of the tape 100 may be decreased,which is problematic. However, the thickness of the base film of thetape of the present invention is not necessarily limited to thenumerical values described above.

Herein, when the tape 100 is used for shading the light, the base film10 may turn black, and when the tape 100 is used for reflecting thelight, the base film 10 may turn white. When the base film 10 colorslike this, the adhesive forces to the first and second adhesive layers30, 40 respectively disposed on upper and lower sides of the base film10 can be improved.

Herein, the black coloring agent may comprise at least one of carbonblack capable of exhibiting black and iron sulfide. Further, the carbonblack may use a urethane-based resin as a binder. The urethane-basedresin has a stable physical property, and an excellent adhesive force toan acrylic-based adhesive layer. In the present invention, the blackcoloring agent may be manufactured by mixing part of various materialsaccording to the color and the physical property as needed. However, theblack coloring agent of the present invention is not limited to thespecific ingredient or the content described above.

The filler layer 20 is formed on the upper side of the base film 10.Further, the thickness of the filler layer 20 varies according to thetotal thickness of the tape 100, and may be, for example, 60-80 μm.

Further, a surface of the filler layer 20 may turn black as needed. Whenthe surface of the filler layer 20 turns black, the function of shadingthe light is given to the filler layer 20 and the degradation of thereliability for partial defects due to the function of shading the lightcan be prevented. Herein, the black coloring agent may comprise at leastone of carbon black and iron sulfide.

In a prior-art tape having a PE-foam structure, a PE-foam may betransferred to a base film or an adhesive layer in contact vertically inreworking. However, since the exemplary embodiment of the presentinvention contains the filler layer 20 and does not use the PE-foam, itdoes not cause such a problem.

Such a filler layer 20 may be formed by coating a paste containing anacrylic binder and the shock resistant filler on the upper side of thebase film 100.

The acrylic binder may be formed of, for example, acrylonitrile.However, the present invention is not limited thereto. Meanwhile, thefiller layer 20 may further comprise additives such as a cross linker, atackifier and the like, as needed. The additives may be added at acontent of 0.1-30 parts by weight, with respect to 100 parts by weightof the acrylic binder. However, the present invention is not limitedthereto.

Further, shock resistance and density of the filler layer 20 may varyaccording to the content of the shock resistant filler contained in theacrylic binder. For example, the shock resistant filler may comprise5-60 parts by weight with respect to 100 parts by weight of the acrylicbinder.

Since the shock resistant filler is an impurity, when it exceeds 60parts by weight with respect to 100 parts by weight of the acrylicbinder, it has a low combination with the acrylic binder. Hence, as thepaste is split and coating is not available, the original function ofthe shock resistant filler cannot be carried out. Further, when thecontent of the shock resistant filler is less than 5 parts by weightwith respect to 100 parts by weight of the acrylic binder, the problemof lowering the shock resistance and repellent resistance may occur.

Further, the shock resistant filler comprises a plurality of hollow fineparticles 21 with low density. Herein, the hollow fine particles 21 haveproper cushiness and can provide excellent shock resistance. As aresult, even if a certain level of vibration or shock is given to theautomobile battery, the shock resistant filler can endure the vibrationor shock, and absorb the vibration or shock to prevent damage of theadhered object.

The hollow fine particles 21 are particles having hollow parts formedtherein, and may be manufactured in various forms in a various methods.Exemplary embodiments will be described below.

Further, the hollow fine particles 21 may comprise liquid hydrocarbonand a first coating film having a hollow part disposed on an outersurface thereof by referring to the liquid hydrocarbon as a nucleatingagent. After the liquid hydrocarbon serves as forming the first coatingfilm, it is removed in a polymerizing process described below.

The liquid hydrocarbon may comprise, for example, 1-10 parts by weightof 2-methyl butane, and 1-10 parts by weight of 2-methyl propane, withrespect to 100 parts by weight of the hollow fine particles 21.

Herein, in the liquid hydrocarbon, when the content of the 2-methylbutane is less than 1 part by weight, inner expansion is insufficient inmanufacture of the hollow fine particles 21, and thus the problem oflowering the shock resistance of the hollow fine particles 21 may occur.Further, when the content of the 2-methyl butane is greater than 10parts by weight, there is overexpansion in manufacture of the hollowfine particles 21, and thus the hollow fine particles 21 do not keep aconstant type to lower uniformity, thereby decreasing an overallphysical property.

Further, when the content of the 2-methyl propane is less than 1 part byweight, inner expansion is insufficient in manufacture of the hollowfine particles 21, and thus the problem of lowering the shock resistanceof the hollow fine particles 21 may occur. Further, when the content ofthe 2-methyl butane is greater than 10 parts by weight, there isoverexpansion in manufacture of the hollow fine particles 21, and thusthe hollow fine particles 21 do not keep a constant type to loweruniformity, thereby decreasing an overall physical property.

The first coating film may comprise a thermoplastic material containinga monomer. The thermoplastic material may comprise 15-40 parts by weightwith respect to a total of 100 parts by weight of the hollow fineparticles 21. The thermoplastic material may comprise, for example, acopolymer of acrylonitrile and other acrylic groups, but thethermoplastic material of the present invention is not limited thereto.The other acrylic groups may comprise phosphate methacrylate, alkalistrippable polyester acrylate and the like.

Herein, when the content of the thermoplastic material is less than 15parts by weight, because it has an impact on crosslink density, acoating treatment may not be smoothly performed. Further, when thecontent of the thermoplastic material is greater than 40 parts byweight, because it has an impact on the content of the shock resistantfiller, the shock resistance and the reliability may be lowered.

The first coating film supplies elastic and restoring forces to the tape100, and supplies the shock resistance thereto to serve as supply of atolerance to mechanical distortion. For example, even if a load of about0.7 Mpa is repetitively applied to the tape 100, the tape 100 is notdamaged with the elastic and restoring forces of the first coating film.

Meanwhile, the hollow fine particles 21 may further comprise a secondcoating film arranged along the circumference of the first coating film,as needed.

The second coating film may comprise 50-80 parts by weight of calciumcarbonate with respect to 100 parts by weight of the hollow fineparticles 21. The second coating film improves a shattering property ofthe liquid hydrocarbon, and improves dispersibility in a resin of thefirst coating film, thereby having an effect of further improving theshock resistance of the hollow fine particles 21.

Further, the second coating can increase a gravity of the hollow fineparticles 21 while preventing the hollow fine particles 21 from beingcondensed in the shock resistant filler, and can serve as improving amixing property.

Herein, when the content of the calcium carbonate is less than 50 partsby weight, workability may be decreased because of shattering the shockresistant filler, and when the content of the calcium carbonate isgreater than 80 parts by weight, the shock resistance may be lowered.

Meanwhile, the diameter of the hollow fine particles 21 of the exemplaryembodiment of the present invention may be 10-50 μm, wherein an innerthrough-hole which the liquid hydrocarbon occupies in the step ofmanufacturing the hollow fine particles 21 accounts for 95%, and thethicknesses of the first and second coating films may be 1 μm or less intotality. The diameter of the hollow fine particles 21 keeps theuniformity of a product in the foregoing scope to minutely adjust thelevel of illumination, thereby ensuring a step compensation of theproduct and stability of the adhesive power. However, the presentinvention is not limited thereto.

Meanwhile, since the filler layer 20 uses the hollow fine particles 21having the uniform diameter described above, it has an excellent levelof illumination in general. In addition, since it is soft like a sponge,it properly fills even the nonuniform level of illumination of aninjection product, thereby securing the adhesive power and thereliability.

The first and second adhesive fillers 30, 40 are formed on an upper sideof the filler layer 20, and a lower side of the base film10,respectively. The first and second adhesive fillers 30, 40 may be formedof, preferably, an acrylic-based pressure sensitive adhesive agent, butthe present invention is not limited thereto. Further, the first andsecond adhesive fillers 30, 40 can adjust the contents of e-EHA, CHMAand nBA, so as to embody excellent water resistance, adhesive power andreliability in polymerization of the acrylic-based adhesive agent.

Herein, the first and second adhesive layers 30, 40 may have differentadhesive powers according to adhered objects. Hence, the first adhesivelayer 30 may be formed to have a different thickness, and, for example,it may be formed to be thicker by about 10 μm than the second adhesivelayer 40 formed between the base film 10 and a release layer 50.

Further, as the first adhesive layer 30 or the second adhesive layer 40gets thicker by a critical thickness, the adhesive power thereof isincreased. Thus, the adhesive layer is made as thick as possible, fromwhich the adhesive power can be improved, and also, the adhesive layeritself can provide a constant cushioning property. When the firstadhesive layer 30 or the second adhesive layer 40 is too thin, theadhesion is lowered, and when the first adhesive layer 30 or the secondadhesive layer 40 is too thick, it may have an impact on blankingmolding in a blanking process.

Further, the first and second adhesive layers 30, 40 controls theirsoftness by adjusting crosslink density, thereby further improving theshock resistance and providing a step compensation effect according to astacking structure. Herein, the crosslink density can be adjusted bycontrolling the kinds and the contents of hardening agents.

The release layer 50 may be formed on a lower side of the secondadhesive layer 40, as needed. The release layer 50 serves as preventingthe finished tape 100 from having foreign substance or being damagedwhen the tape 100 is stored or transported.

The release layer 50 can uses, for example, a product in which a PE filmis connected to paper, and silicon is release-treated on an outersurface of the PE film. However, the present invention is not limitedthereto. Acryl and silicon are incompatible and are not thus coupled toeach other, and as a result, an acrylic adhesive agent may use a productin which the release film is silicon-treated. For example, the releaseproduct 50 may use the product in which silicon is release-treated inglassine and PET goods.

In an exemplary embodiment of the present invention, the thickness ofthe paper may be 70-80 μm, and the PE film of which the thickness is30-40 μm may be used on its double sides. Further, for therelease-treatment of the silicon, the silicon may be coated with a thinfilm having a thickness of 1 μm or less. Herein, according to the kindof the used silicon, release powers and transition rates of the releaselayer 50 may be different, and, typically, the release layer 50 uses thetransition rate of 90% or more. Herein, the transition rate indicates anumerical value of moving silicon to acryl, wherein the low transitionrate indicates the small change in a physical property.

Herein, from the comparison between the comparative examples and theembodiments of the present invention, the excellent characteristics ofthe double-sided tape according to the embodiments of the presentinvention will be described below.

Comparative Example 1 shows a double-sided tape having an acrylic-foamstructure having a total thickness of 200 μm, Comparative Examples 1 to4 show double-sided tapes having polyethylene-foam structures of whichtotal thicknesses are 250 μm, 200 μm and 200 μm, respectively, andEmbodiments 1 to 3 show double-sided tapes having filler layers of whichtotal thicknesses are 200 μm, 250 μm and 300 μm, respectively.

Herein, in Embodiment 1, the thicknesses of the first and secondadhesive layers were 60 μm, and the thickness of the filler layer was 60μm. In Embodiment 2, the thicknesses of the first and second adhesivelayers were 70 μm, and the thickness of the filler layer was 70 μm. InEmbodiment 3, the thicknesses of the first and second adhesive layerswere 90 μm, and the thickness of the filler layer was 80 μm. InEmbodiments 1 to 3, the contents of the shock resistant fillers in allthe filler layers used 35 parts by weight with respect to 100 parts byweight of the acrylic binder.

Hereinafter, Embodiments 1 to 3 will be referred to as “the embodiments”and described as needed when describing features irrelevant to the totalthickness.

An adhesive power test is called an ASTM D 3330 test, wherein thedouble-sided tapes of the comparative examples and the embodimentsadhered to an SUS board, a PC board and glass, respectively, byreciprocating 2 kg of a rubber compressing roller one time at a velocityof 300 mm/min, and then, they were left for 30 minutes at roomtemperature. The forces (gf/25 mm) of detaching the double-sided tapesfrom adhered objects were measured.

With reference to FIG. 2, as a result of the measurement, it can beconfirmed that both upper and lower sides in Embodiments 1 to 3 aresimilar to or have relatively higher force values than those ofComparative Examples 1 to 4. Thus, it can be known that the double-sidedtapes having the filler layers of the embodiment of the presentinvention are similar to or have more excellent adhesion than thedouble-sided tapes having the acrylic foam or the PE-foam (ComparativeExamples 1 to 4).

As a result, the comparative examples should additionally use anadhesive so as to reduce a difference of such adhesion. The use of theadhesive makes it impossible to carry out rework of separating thedouble-sided tape from the adhered object and reassembling it as needed,and also leads to several problems such as rise in costs, a complicatedmanufacturing process and the like.

The test of the shock resistance is for measuring a restoring forceaccording to pressure applied to the product. With reference to FIG. 3,as a result of the measurement, the embodiments have a smaller change inthe thickness as per the pressure applied to the product than thecomparative examples, and have a smaller compression rate as per thepressure applied to the product than the comparative examples. Herein,the unit of a compression thickness is μm, the unit of a compressionstr. is mPa, and the unit of a compression rate is %. In the test of theshock resistance, conventional products using the PE-foam are used onlyin Comparative Examples 2 and 3.

In general, when the tapes adhere to an upper plate and a lower plate,there may be cracks or peeling on the adhered upper and lower plates dueto artificial impacts. The test result shows that in the comparativeexamples, when the characteristic of low elasticity and low density andthe pressure are applied to the tapes, they have slow restoring forces.In contrast, in the embodiments, the shock resistant filler formed ofthe hollow fine particle of the filler layer play a role as a spring toimprove the shock resistance with the characteristic of high elasticityand high density, and when pressure is applied to the tapes, they havefast restoring forces.

It can be expected that the shock resistance of the tape according tothe exemplary embodiments of the present invention is more improved byaverage 300% or more than the comparative examples. Thus, theembodiments have a compression rate of about 50% for the comparativeexamples, and have excellent repellent resistance to restrain impactsfrom being applied to an ITO sensor although the tape is not made thick.Thus, it can be known that even if the product having a thickness of 300μm to which the comparative examples applies is manufactured to have thethickness of 200-250 μm in the embodiments, it can exhibit the shockresistance equal to or superior to that of the embodiments.

Meanwhile, the difference of the shock resistance of the tape may causea remarkable difference even in a waterproof property of the adheredobject because of the cracks or peeling. That is, even if the tapes aremanufactured to have the same thickness, the tapes in the comparativeexamples and the embodiments have remarkably different shock resistance.

In other words, according to the embodiments of the present invention,waterproofing performance of IP×7 or more can be implemented due to suchshock resistant difference, while the comparative examples implementsmuch lower waterproofing performance than the embodiments. Herein, IPmeans IP_Ingress Protection rating, the first number x indicatesclassifying a grade for a dust proof function into 0-6, and the secondnumber indicates classifying a grade for a waterproof function into 0-9k. A higher number indicates excellent performance.

Further, in the tapes according to the embodiments of the presentinvention, since pressure in adhering by the filler layer focuses on abinding portion to easily extrude air present in an adhesion interface,excellent adhesion that prevents a gap through which water arepenetrated can be implemented, in connecting rigid bodies, therebyimproving a waterproof property.

Further, according to the exemplary embodiment of the present invention,a thickness direction of the tape has more excellent step compensationby the filler layer than the comparative example, which can give a greatadvantage to the waterproof property.

Meanwhile, the conventional tapes have a so-called open cell structurethat a foaming agent is inserted into a PE resin in manufacture to makeopenings, and the openings give rise to cushiness. Herein, they haveproblems such as a big thickness deviation of 20-30 μm, and an ununiformsurface.

However, the waterproof tape 100 according to the exemplary embodimentof the present invention does not use such a PE-foam, and has aso-called closed cell structure using the shock resistance filler layer.Thus, in accordance with the embodiment, since the thickness of the tapeis adjusted by coating unlike the conventional double-sided tape havingthe open cell structure, the tape can have a uniform thickness on thewhole. Also, since the filler layer is formed by a coating process, itsthickness can be easily adjusted to have excellent productivity andwetting. In the conventional PE-foam, it is difficult to have adistribution value of a uniform thickness.

In addition, the tensile strength of the adhesive layer and the fillerlayer may be about 2 kgf/mm², and the physical property may be 30kgf/mm² or less according to the tensile strength of PET as the basefilm.

The waterproof tape of the embodiment has easy adhesion to the adheredobject, and can effectively prevent penetration of water from a tightgap to have an excellent waterproof property. However, the waterprooftape enables slimness, and can be also used effectively in fastening ofan automobile battery assembly requiring strict watertightness.

Hereinafter, a method for manufacturing a waterproof tape 100 accordingto an exemplary embodiment of the present invention will be describedbelow.

FIG. 4 is a flowchart of a method for manufacturing a waterproof tapeaccording to an exemplary embodiment of the present invention.

With reference to FIG. 4, the base film 10 is first prepared (S1).Herein, the base film 10 may turn black as needed. Further, the blackcoloring agent may use at least one of carbon black and iron sulfide.Furthermore, it is preferable to properly mix and use the carbon blackor the iron sulfide to prevent part of the base film 10 from beinglumped to turn. The carbon black or the iron sulfide is preferablysufficiently stirred at 300 rpm or less for 10-30 minutes so as not toaffect uniform stirring and a physical property. However, the presentinvention is not limited thereto.

Next, the filler layer 20 is formed by coating a paste containing ashock resistance filler having the acylic binder and a plurality ofhollow fine particles 21 on the upper side of the base film 10 (S2).Herein, the shock resistant filler may comprise 5-60 parts by weightwith respect to 100 parts by weight of the acrylic binder. Further, itmay further comprise an additive containing 0.1-30 parts by weight of across linker, as needed. Herein, the filler layer 20 may turn black asneeded.

FIG. 5 is a flowchart of a method for manufacturing a shock resistantfiller of the filler layer in the waterproof tape according to anexemplary embodiment of the present invention. With reference to FIG. 5,an exemplary embodiment of a method for manufacturing the hollow fineparticle is described as follows.

First, 2-20 parts by weight of liquid hydrocarbon and a dispersing agentare inputted into 0.1-1 parts by weight of water, with respect to atotal of 100 parts by weight of the follow fine particle 21. Herein, theliquid hydrocarbon may comprise, for example, 1-10 parts by weight of2-methylbutane and 1-10 parts by weight of 2-methylpropane. Further, thedispersing agent may be a moderate amount of a surfactant. Thereafter,the hydrogen dispersion is prepared by dispersing the liquid hydrocarbonnot mixed with water, at a certain size, by using the surfactant (S21).

Further, herein, additives such as a cross linker and the like may befurther inputted thereto, as needed. The size limitation of theadditives can be adjusted by the gravity. When the size of the fillergets bigger, and porous layers of the hollow fine particles grow bigger,the filler layer 20 has a low gravity, and when the filler gets smallerthan the standard, the porous layers of the hollow fine particles getsmaller, and the gravity thus grows bigger.

Thereafter, a thermoplastic material containing a monomer is inputtedinto the dispersed liquid hydrocarbon, the dispersed liquid hydrocarbonis referred to as a nucleating agent, and then, a first coating filmhaving a band shape to surround the liquid hydrocarbon is formed,thereby preparing a particulate crystal (S22).

Herein, the monomer may comprise a copolymer of 15-40 parts by weight ofacrylonitrile with respect to a total of 100 parts by weight of thehollow fine particles and other acylic groups.

Thereafter, the particulate crystal having the first coating film formedthereon is polymerized (S23). The polymerization is that for example,0.1-5.0 parts by weight of a polymerization initiator is added to theliquid hydrocarbon and is heated at a temperature of 140-150° C. for10-60 minutes, from which the particulate crystal is heated to removethe hydrocarbon, thereby preparing an unexpanded microsphere is prepared(S24). Herein, the polymerization may proceed through a manner ofseparating the first coating film from the liquid hydrocarbon with adifference of the gravity, as needed.

Thereafter, the unexpanded microsphere is heated, for example, for 10-60minutes to expand the diameter of the first coating film, and as aresult, an expanded microsphere having an expanded volume in comparisonwith the originally provided unexpanded microsphere is prepared (S25).Herein, the unexpanded microsphere may be heated, for example, for110-190° C., and more preferably, for 130-170° C. However, the presentinvention is not limited thereto. When the heating temperature is lessthan 110° C., microsphere is insufficiently expanded, which may lead tothe problem of lowering repellent resistance and chemical stability ofthe hollow fine particles. Further, when the heating temperature isgreater than 190° C., since the repellent resistance is lowered,chemical resistance and storage stability are vulnerable, and it may bedifficult to implement the characteristic of the product.

That is, when the liquid hydrocarbon is referred to as the nucleatingagent, and the outer wall is surrounded by an acrylic monomer, theparticulate crystal is polymerized to remove the liquid hydrocarbon.Then, the first coating film is expanded to form the microsphere whichhas the porous layer formed thereon, has a hollow part and has anexpanded volume, thereby manufacturing the shock resistant filler havingthe expanded microsphere.

Thereafter, a second coating film containing 50-80 parts by weight ofcalcium carbonate with respect to a total of 100 parts by weight of thehollow fine particles may be further disposed on the circumference ofthe first coating film of the expanded microsphere, as needed.

With reference to FIG. 6, in the second coating film, for example, theexpanded microsphere (M) and calcium carbonate (C) are inserted into amain body 210 of a reactor 200 through injection parts 221, 224 formedin a pipe shape, and hot air having a temperature of about 130-150° C.is inserted thereto through an air supply part 251, thereby allowing theexpanded microsphere (M) and the calcium carbonate (C) to float in themain body 210 of the reactor 200. In this state, the second coating filmmay be progressed to be formed while the calcium carbonate (C) bumpsagainst the circumference of the first coating film of the expandedmicrosphere (M) and is embedded therein.

Herein, the velocity of supplying the air inserted into the main body210 of the reactor 200, and the like, can be controlled to the extentthat the expanded microsphere (M) and the calcium carbonate (C) canproperly float and flow in the main body 210 of the reactor 200.Further, in the main body 210, a rotating shaft 231 having a propeller231 a may be installed to circulate the inserted air, the expandedmicrosphere (M) and the calcium carbonate (C) and to more smoothly formthe second coating film.

Further, the temperature of the air makes the first coating film tenderto easily embed the calcium carbonate (C) on the circumference thereof.However, the temperature of the air according to the present inventionis not limited thereto. Furthermore, in a lower end of the main body210, a discharge part 241 having a valve 241 a may be prepared todischarge the microsphere (M) having the second coating film formedthereon.

The second coating film serves as restraining condensation and ashattering property of the expanded microsphere (M). Further, thedensity is measured by comparing the amount of the thermoplasticmaterial inputted in the foregoing step and the amount and weight of aplurality of hollow fine particles finally completed, as needed. Thus,the density can be uniformly maintained at all times. Furthermore, thefiller in the embodiments is light in a hardening process to floats atthe top, all of which escapes in air.

Meanwhile, by randomly extracting samples and measuring their gravities,it can be confirmed whether the filler layer 20 has a uniformly sizeddistribution or not. When the filler layer 20 comprises large numbers ofbig fillers, it is lighter than a suitable standard sample, and when itcomprises large numbers of small fillers, it is heavier than thesuitable standard sample.

In accordance with the embodiments, as described above, the danger ofextinguishing the liquid hydrocarbon in the filler layer at a hightemperature, and shattering the particles of the porous layer may occur.However, the second coating film gives a fixed weight to the expandedmicrosphere (M) to improve the dispersibility of the first coating filmof the expanded microsphere (M). As a result, the second coating filmserve as preventing the hollow fine particles 21 from be shattered, andcan provide an effect of improving the shock resistance of the hollowfine particles 21.

Further, the second coating can serve as increasing gravities of thehollow fine particles 21 while preventing the hollow fine particles 21from being condensed in the shock resistant filler, and can serve asimproving a mixing property.

Herein, the second coating film may comprise 50-80 parts by weight ofcalcium carbonate with respect to 100 parts by weight of the hollow fineparticles 21. Herein, when the content of the calcium carbonate is lessthan 50 parts by weight, workability may be decreased because ofshattering the shock resistant filler, and when the content of thecalcium carbonate is greater than 80 parts by weight, the shockresistance may be lowered.

Next, the first and second adhesive layers 30, 40 are formed on theupper side of the filler layer 20 and the lower side of the base film10, respectively (S3).

Next, the release layer 50 is formed on the lower side of the secondadhesive layer 40 to complete the waterproof tape (S4).

The present invention should not be construed as limited to theembodiments set forth herein and the accompanying drawings, and is onlydefined by scopes of claims.

Thus, it will be apparent to those skilled in the art that replacements,modifications, and variations can be made without departing from thespirit and scope of the invention.

-   -   10; a base film    -   20; a filler layer    -   21; hollow fine particles    -   30, 40; first and second adhesive layers    -   50; a release layer    -   100; a tape    -   200; a reactor

What is claimed is:
 1. A waterproof tape for an automobile battery comprising a base film having a filter layer formed on one side thereof and an adhesive layer, wherein the filler layer comprises a shock resistant filler containing an acrylic binder and a plurality of hollow fine particles, and the hollow fine particle comprises a first coating film which consists of a thermoplastic material containing 15-40 parts by weight of a monomer, with respect to a total of 100 parts by weight, and has a hollow part.
 2. The waterproof tape for an automobile battery of claim 1, wherein the hollow fine particles further comprise a second coating film containing 50-80 parts by weight of calcium carbonate, with respect to a total of 100 parts by weight, and disposed arranged along the circumference of the first coating film.
 3. The waterproof tape for an automobile battery of claim 1, wherein the filler layer comprises 5-60 parts by weight of the shock resistant filler, with respect to 100 parts by weight of the acrylic binder.
 4. The waterproof tape for an automobile battery of claim 1, wherein the monomer of the first coating film is a copolymer comprising at least one of 15-40 parts by weight of acrylonitrile, with respect to 100 parts by weight of the hollow fine particles, phosphate methacrylate and alkali strippable polyester acrylate.
 5. The waterproof tape for an automobile battery of claim 1, wherein the base film turns black, and the black coloring agent comprises at least one of carbon black and iron sulfide.
 6. The waterproof tape for an automobile battery of claim 1, wherein the filler layer turns black, and the black coloring agent comprises at least one of carbon black and iron sulfide.
 7. A method for manufacturing a waterproof tape for an automobile battery by forming an adhesive layer on at least one side of a base film, wherein the base film forms a filler layer by coating a paste comprising a shock resistant filler having an acrylic binder and a plurality of hollow fine particles on one side thereof, and the hollow fine particles are manufactured by the steps of: preparing a hydrogen dispersion by inputting 2-20 parts by weight of liquid hydrocarbon with respect to a total of 100 parts by weight and a dispersing agent into water; preparing a particulate crystal by inputting 15-40 parts by weight of a monomer into the hydrogen dispersion, with respect to a total of 100 parts by weight of the hollow fine particles, and forming a first coating film on the circumference of the hydrocarbon; forming an unexpanded microsphere by heating the particulate crystal and removing the hydrocarbon; and preparing an expanded microsphere by heating the unexpanded microsphere to expand the first coating film.
 8. The method for manufacturing a waterproof tape for an automobile battery of claim 7, wherein the hollow fine particles are manufactured by further comprising the step of forming a second coating film with 50-80 parts by weight of calcium carbonate with respect to a total of 100 parts by weight of the hollow fine particles, on the circumference of the first coating film of the expanded microsphere.
 9. The method for manufacturing a waterproof tape for an automobile battery of claim 7, wherein the liquid hydrocarbon comprises 1-10 parts by weight of 2-methylbutane and 1-10 parts by weight of 2-methylpropane, with respect to a total of 100 parts by weight of the hollow fine particles, in the step of preparing the hydrogen dispersion.
 10. The method for manufacturing a waterproof tape for an automobile battery of claim 7, wherein the dispersing agent is a surfactant in the step of preparing the hydrogen dispersion.
 11. The method for manufacturing a waterproof tape for an automobile battery of claim 7, wherein the monomer is a copolymer of 15-40 parts by weight of acrylonitrile with respect to a total of 100 parts by weight of the hollow fine particles and other acrylic groups, in the step of preparing the particulate crystal.
 12. The method for manufacturing a waterproof tape for an automobile battery of claim 7, wherein the unexpanded microsphere is heated at a temperature of 70-190° C., in the step of preparing the expanded microsphere.
 13. The method for manufacturing a waterproof tape for an automobile battery of claim 7, where the step of forming the second coating film comprises the steps of: inputting the expanded microsphere and the calcium carbonate into a reactor, and inserting air thereto at a temperature of 130-150° C., thereby floating the expanded microsphere and the calcium carbonate inside the reactor; and forming a second coating film while embedding the calcium carbonate on an outer wall of the first coating film of the expanded microsphere.
 14. The method for manufacturing a waterproof tape for an automobile battery of claim 7, wherein the base film turns black, and the black coloring agent comprises at least one of carbon black and iron sulfide.
 15. The method for manufacturing a waterproof tape for an automobile battery of claim 7, wherein the filler layer turns black, and the black coloring agent comprises at least one of carbon black and iron sulfide. 